public static string GetPayPalSubscriptionURL(string item_name, string item_number, string amount, int months, string username)
        {
            int RecurringPaymentOPtion = 1;     // // Recurring payments. Subscription payments recur unless subscribers cancel their subscriptions before the end of the current billing cycle or you limit the number of times that payments recur with the value that you specify for srt.
                                                //Allowable values are:
                                                //0 – subscription payments do not recur
                                                //1 – subscription payments recur
            string CustomFieldValue = username; //User-defined field which PayPal passes through the system and returns to you in your merchant payment notification email. Subscribers do not see this field.
                                                //The default is 0.
                                                // t1
                                                //See description.
                                                //Trial period 1 units of duration. Required if you specify a1.
                                                //Allowable values are:

            //D – for days; allowable range for p2 is 1 to 90
            //W – for weeks; allowable range for p2 is 1 to 52
            //M – for months; allowable range for p2 is 1 to 24
            //Y – for years; allowable range for p2 is 1 to 5
            string strURL = "https://www.sandbox.paypal.com/cgi-bin/webscr";

            if (Paypal_Live_Status() == 1)
            {
                strURL = "https://www.paypal.com/cgi-bin/webscr";
            }
            string BaseUrl    = Config.GetUrl();
            string cancel_url = BaseUrl + "paypal/subscription/cancel.aspx";
            string return_url = BaseUrl + "paypal/subscription/confirmation.aspx";
            string notifyUrl  = BaseUrl + "paypal/ipn.aspx";
            //string image_url = HttpUtility.UrlEncode(BaseUrl + "images/logo/classified_header.jpg");
            string        image_url   = ""; // paypal header url
            string        paypal_logo = WebUtility.UrlEncode(BaseUrl + "images/logo.png");
            StringBuilder Url         = new StringBuilder();

            Url.Append(strURL + "?cmd=_xclick-subscriptions&business=" + PaypalBLL.Paypal_Receiver_Email() + "&item_name=" + WebUtility.UrlEncode(item_name) + "&a3=" + amount + "&p3=" + months + "&t3=M&currency_code=USD&notify_url=" + notifyUrl + "&return=" + return_url + "&cancel_return=" + cancel_url + "&cpp_header_Image=" + image_url + "&cpp_headerback_color=ECDFDF&cpp_headerborder_color=A02626&cpp_payflow_color=ECDFDF&image_url=" + paypal_logo + "&src=" + RecurringPaymentOPtion + "&custom=" + CustomFieldValue + "");
            return(Url.ToString());
        }
        public static string GetPayPalUnsubscriptionURL(string email)
        {
            //The default is 0.
            // t1
            //See description.
            //Trial period 1 units of duration. Required if you specify a1.
            //Allowable values are:

            //D – for days; allowable range for p2 is 1 to 90
            //W – for weeks; allowable range for p2 is 1 to 52
            //M – for months; allowable range for p2 is 1 to 24
            //Y – for years; allowable range for p2 is 1 to 5
            string strURL = "https://www.sandbox.paypal.com/cgi-bin/webscr";

            if (PaypalBLL.Paypal_Live_Status() == 1)
            {
                strURL = "https://www.paypal.com/cgi-bin/webscr";
            }
            string BaseUrl    = Config.GetUrl();
            string cancel_url = BaseUrl + "paypal/unsuscribe/cancel.aspx";
            string return_url = BaseUrl + "paypal/unsuscribe/confirmation.aspx";
            string notifyUrl  = BaseUrl + "paypal/ipn.aspx";
            //string image_url = HttpUtility.UrlEncode(BaseUrl + "images/logo/classified_header.jpg");
            string        image_url   = ""; // paypal header url
            string        paypal_logo = WebUtility.UrlEncode(BaseUrl + "images/logo.png");
            StringBuilder Url         = new StringBuilder();

            Url.Append(strURL + "?cmd=_subscr-find&alias=" + WebUtility.UrlEncode(email) + "&business=" + PaypalBLL.Paypal_Receiver_Email() + "&notify_url=" + notifyUrl + "&return=" + return_url + "&cancel_return=" + cancel_url + "&cpp_header_Image=" + image_url + "&cpp_headerback_color=ECDFDF&cpp_headerborder_color=A02626&cpp_payflow_color=ECDFDF&image_url=" + paypal_logo + "");
            return(Url.ToString());
        }
        public static string GetPayPalPaymentUrl(string item_name, string item_number, string amount, string quantity, string username)
        {
            string strURL = "https://www.sandbox.paypal.com/cgi-bin/webscr";

            if (Paypal_Live_Status() == 1)
            {
                strURL = "https://www.paypal.com/cgi-bin/webscr";
            }
            string BaseUrl    = Config.GetUrl();
            string cancel_url = BaseUrl + "paypal/cancel";
            string return_url = BaseUrl + "paypal/confirmation";
            string notifyUrl  = BaseUrl + "paypal/index";
            //string image_url = HttpUtility.UrlEncode(BaseUrl + "images/logo/classified_header.jpg");
            string        image_url        = ""; // paypal header url
            string        paypal_logo      = WebUtility.UrlEncode(BaseUrl + "images/logo.png");
            StringBuilder Url              = new StringBuilder();
            string        CustomFieldValue = username; //User-defined field which PayPal passes through the system and returns to you in your merchant payment notification email. Subscribers do not see this field.

            Url.Append(strURL + "?cmd=_xclick&upload=1&rm=2&no_shipping=1&no_note=1&currency_code=USD&business=" + PaypalBLL.Paypal_Receiver_Email() + "&item_number=" + item_number + "&item_name=" + item_name + "&amount=" + amount + "&quantity=" + quantity + "&undefined_quantity=0&notify_url=" + notifyUrl + "&return=" + return_url + "&cancel_return=" + cancel_url + "&cpp_header_Image=" + image_url + "&cpp_headerback_color=ECDFDF&cpp_headerborder_color=A02626&cpp_payflow_color=ECDFDF&image_url=" + paypal_logo + "&custom=" + CustomFieldValue + "");
            return(Url.ToString());
        }